The present invention relates generally to a hinge preferably used in opening and closing various opening and closing members of devices such as a calculator, a clock, a portable telephone, a portable computer, an electronic notebook, or the like, relative to a main body of the device, and in particular, to a hinge which rotates opening and closing members from a closed position on the device to an open position, preferably for supporting the device on a horizontal surface.
There have been publicly known various structures of hinges in which various cams and springs are integrated to maintain a cover or lid at an arbitrary or a predetermined opening angle relative to a main body of a device. However, many of these known structures are excessively complicated and have high fabrication costs.
U.S. Pat. No. 5,436,954 to Nishiyama discloses a portable telephone having a rotatable display panel hingedly connected to a key pad casing. A tension coil spring is housed in the casing and connected to the casing and the display panel at each of its respective ends. The spring asserts a rotational force on the display panel causing the display panel to automatically rotate to its open position.
U.S. Pat. No. 5,568,358 to Nelson et al. is directed to a portable signal processing communications device having a hingedly connected lid which covers a display screen when in a closed position and is manually rotated rearwardly, by hand, to form a support for maintaining the device in a tilted position on a horizontal surface.
U.S. Pat. No. 4,703,160 to Narishima, et al. discloses a casing structure for a portable electronic device having hingedly connected covering portions which are folded backward to form a stand for maintaining the device in an inclined position on a horizontal surface.
U.S. Pat. No. 6,178,085 to Leung discloses a calculator having a pre-stressed torsional spring and damping drum assembly that pivots a lid from a closed position over a display screen to a standing position. The pre-stressed torsional spring and damping drum assembly is housed in a bore in the lid.
A portable calculator having hinged cover attached to an end of the calculator casing is disclosed in U.S. Pat. No. 4,259,568 to Dynesen. The cover is formed by a first part and a second longer part connected by a hinged joint. The second longer part projects below the bottom of the calculator and the first part extends at an angle when the cover forms a stand. When not in use, the hinged covers may be folded forwardly and laid flat over the surface of the calculator to form a protective flat cover extending over the entire front surface of the calculator.
A portable telephone having a hinge assembly that urges a cover from a closed position to an open position upon releasing a latch is disclosed in U.S. Pat. No. 5,987,122 to Daffara et al.
U.S. Pat. No. 5,607,054 to Hollingsworth discloses a carrying case for a notebook computer having front and back panels which cover the computer. The front panel is adapted to be folded rearwardly to form a stand that supports the notebook computer in an inclined position.
While the above described prior art discloses different types of hinges for electronic and mechanical apparatuses, a need remains for a simple and economical structure for a hinge that rotates a pivotably connected cover from a closed position to an open position, which avoids the complexity and expense of the prior art.
The invention provides a hinge for a rotatably connected cover which is mechanically simple in design and inexpensive to manufacture and maintain.
In accordance with the invention, a hinge is provided for rotating a cover pivotably connected to a device housing from a closed position to an open position. A shaft is connected to the cover. The shaft and cover have a common axis of rotation. A spring adjacent one side of the housing has a top end and a bottom end which is affixed at its bottom end to the device housing. A line has a first end connected to the top end of the spring and a second end wound onto the shaft. When the cover is in the closed position, the spring is in an extended state. Upon release of the cover from the closed position, the spring force returns the spring toward a neutral state, thereby unwinding the line from the shaft and causing rearward rotation of the cover to the open position.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.